Voltage regulator circuits may provide a predetermined output voltage even if a load connected to an output terminal of the voltage regulator circuit consumes varying energy amount, i.e. energy deposited in the load varies. The voltage regulator circuit is operated at a supply voltage (VDD) which is determined by the operation environment of the voltage regulator circuit. The operation environment of the voltage regulator circuit may be a mobile phone, a notebook computer, a personal computer, etc.
In normal operation, the supply voltage (VDD) of the voltage regulator circuit exceeds the output voltage provided by the voltage regulator circuit. A large difference between the supply voltage and the output voltage of the voltage regulator circuit may result in increased power dissipation within the voltage regulator circuit, which in turn results in reduced battery-operating time, especially for mobile devices.
In order to adapt the supply voltage to a desired output voltage, i.e. in order to provide a predetermined voltage difference between the supply voltage and the output voltage, an operation of the voltage regulator circuit using different supply voltages may reduce overall power consumption of an electronic device which includes the voltage regulator circuit. Thus, switching over between different supply voltages in an efficient manner using an electronic circuit with low chip area consumption is an issue.